We propose to produce a 3D digital atlas of the C57BL6/J mouse brain by magnetic resonance microscopy (MRM). The atlas will be designed to serve as a general template for spatial mapping of all genetic information in the mouse brain and will be available to all molecular biologists. We will achieve 10 x 10 x 10 mum3 spatial resolution in the 3D MRM atlas through application of available technologies at the Center for In Vivo Microscopy and via development of new "active" proton staining technologies. The 3D MRM atlas will be available in at least three different endogenous and "active" proton stains. Further, a probabilistic (averaged from many brain specimens) atlas with error estimations will be created for registration of actual gene-expression data.